1. Field
The present disclosure of invention relates to an organic light emitting diodes (OLED's) display having differently colored OLED's and to a driving method thereof.
2. Description of Related Technology
Display devices are used for displaying images for portable and/or handheld apparatuses such as personal computers, mobile phones, and PDAs, or as monitors for various types of information devices. The display devices may be of different kinds including a liquid crystal display device (LCD) using an LCD panel, an organic light emitting diode (OLED) display using organic light emitting elements, a plasma display panel (PDP) using a plasma panel, and the like. Particularly, OLED display have come into the spotlight, because they have high light-emitting efficiency, good and luminance, a wide viewing angle, and a fast response speed.
The typical organic light emitting diode (OLED) is formed as a deposition thin film structure including a photons emitting layer (EML) and a holes transport layer (HTL) disposed between a cathode electrode and an anode electrode. Also, for increasing luminous efficiency through improvement of the injection and movement characteristics of the electrons and of the holes, the organic light emitting element may further include an electrons injecting layer (EIL), a holes injection layer (HIL), and a holes blocking layer (HBL).
In general, the organic light emitting diode (OLED) display is formed as a plurality of multi-color unit pixels by including a red subpixel, a green subpixel, and a blue subpixel in each unit pixel, thereby displaying images of various colors. However, the electro-optical characteristics of the organic light emitting materials that respectively output different colors such as the red, the green, and the blue colors are different from one another such that different operating voltages are developed in the driving of the red, green, and blue subpixels.
In general, the driving of the OLED's is current based and the power supply voltages for driving the red, green, and blue subpixels are set to be the same for each of the subpixels with reference to a full white grayscale. In this case, the differences of the operating voltages of the red, green, and blue subpixels are not considered such that unnecessary power wastage occurs because an excessively large power supply voltage is used for those of the different OLED's that have the lowest operating voltages.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.